The World’s Best Chicken | Rachel Schultz. 1 pound boneless, skinless chicken breasts 1/2 cup Dijon mustard 1/4 cup maple syrup 1 tablespoon red wine vinegar Salt & Pepper Rosemary Preheat oven to 400 degrees. In a small bowl, mix together mustard, syrup, and vinegar. Place chicken breasts into 9×13 baking dish. Season with salt and pepper.